Microstructure, magnetic and magnetocaloric properties in magnetic-field-induced martensitic transformation Mn1-xCo1+xGe alloy ribbons

The sharp field induced metamagnetic martensitic transformation plays a pivotal role in magnetoresponsive effects for ferromagnetic shape memory alloys (FSMAs). Homogeneous polycrystalline Mn1-xCo1+xGe alloy ribbons are prepared by using the arc-melting and melt-spinning technique in this work. The microstructure, crystalline structure, magnetic and magnetocaloric properties are studied in these ribbons. The substitution of Co for Mn reduces the structural transformation temperature, which leads to the realization of coincident magnetostructural transformation. Strikingly, a magnetic-field-induced martensitic transformation is observed in these ribbons. Therefore, large magnetocaloric effect, including maximum magnetic entropy change (Delta S-M,S-max) value of similar to 28 and 25 Jkg(-1)K(-1) and effective refrigeration capacity (RCeff) of similar to 168 and 181 Jkg(-1) are obtained for x = 0.035 and 0.09 samples, respectively, under the field change of mu(0)Delta H = 0-7 T. Furthermore, the average hysteresis loss of these ribbons reduces largely in contrast to their bulk counterparts. These results would provide the new experimental data for magnetic refrigerant materials and pave the way for the further investigation of other FSMAs. (C) 2019 Elsevier B.V. All rights reserved.